The present invention relates to an ink liquid supply system for an ink jet system printer of the charge amplitude controlling type and, more particularly, to a constant flow rate pump for use in the ink liquid supply system.
A constant flow rate ink liquid supply pump is highly required in an ink jet system printer of the charge amplitude controlling type to ensure an accurate printing. In addition, in an ink jet system printer of the charge amplitude controlling type, ink droplets not contributing to an actual printing operation are collected by a beam gutter and returned to an ink liquid supply system for recirculation purposes. Therefore, a reliable recirculation system is required in the ink jet system printer of the charge amplitude controlling type.
In the conventional ink jet system printer of the charge amplitude controlling type, a constant pressure ink liquid supply pump is employed, wherein the mass of the ink droplets and the velocity of the ink droplets emitted from a nozzle are variable depending on the ink characteristics such as the viscosity. These variations will provide a distortion on the printed character. Moreover, in the conventional ink jet system printer of the charge amplitude controlling type, the ink recovery is conducted through the use of the gravity. Accordingly, the ink liquid recirculation is not stable when the viscosity or the surface tension of the ink liquid varies.
Accordingly, an object of the present invention is to provide a constant flow rate pump for use in an ink liquid supply system of an ink jet system printer of the charge amplitude controlling type.
Another object of the present invention is to provide a constant flow rate pump of small size.
Still another object of the present invention is to provide a small pump which integrally includes a pressure chamber for supplying the ink liquid to a nozzle and another pressure chamber for introducing waste ink liquid from a beam gutter of the ink jet system printer of the charge amplitude controlling type.
Yet another object of the present invention is to provide a novel ink liquid sypply system in an ink jet system printer of the charge amplitude controlling type.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
To achieve the above objects, pursuant to an embodiment of the present invention, a pump integrally includes two pressure chambers, one being determined by one end of a piston, and the other being determined by a diaphragm secured to the other end of the piston. The first pressure chamber functions to introduce the waste ink liquid collected by a beam gutter of the ink jet system printer of the charge amplitude controlling type. The second pressure chamber functions to develop the ink liquid toward a nozzle of the ink jet system printer of the charge amplitude controlling type at a constant flow rate.